Flowering time in P. sativum has been studied since Mendels time in the 19th century, but remains very much studied today because of its effect on plant fitness. In this project, two major flowering genes, Late flowering (Lf) and High response (Hr) were studied to search for polymorphisms that could explain the variation in flowering time in pea. Accessions from different parts of Europe were cultivated and their flowering time recorded. To investigate if flowering time shows adaption to the environment, both latitude and Hardiness zones were used as ecological variables to explain variation in flowering time. In addition, genetic similarity between peas from the same geographical regions was investigated by constructing polygenetic trees.

Sequencing revealed that there was little variation in the Lf gene, though, one nucleotide substitution in exon 4 was present in two accessions and their flowering time was significantly later than the majority of pea accessions used in this study. In the Hr gene 20 of the 47 accessions had the hr allele and their flowering time that was significant earlier than the accessions with the Hr allele. Due to low nucleotide diversity in both Lf and Hr, it was difficult to make up any geographical clustering within these genes. Expression analysis of Lf showed a strong correlation with flowering time, confirming the influence Lf has on flowering time. However, no polymorphisms in these accessions correlated with the Lf expression, suggesting that regulation of the gene expression rather than differences in the protein coding gene controls flowering time.